USB Charge Doctors Not Measuring Amps Moderators: adafruit_support_bill, adafruit

[Nickel33]

The "USB Charge Doctors" Product ID: 1852 appear to be defective. The units measure voltage but not current. I have tested the devices by comparing the results to a known good unit and the newer units always show zero amps (they pass current, but don't measure it). This test can be easily duplicated by putting two meters in series with one another and charging a lithium battery (for example).

Good (older) unit on top, Bad (newer) unit on bottom.

IMG_20190524_095747 (600x800).jpg (268.8 KiB) Viewed 297 times

More information: I have four "USB Charge Doctors" that were purchased in two separate orders. The one unit that works was purchased on March 7, 2019 order number 1998623-2738614792. The three units that do not work were purchased on May 5, 2019 order number 2049404-3931242225.

Note Rotated three-pin IC on right side.

IMG_20190524_095003 (600x800).jpg (304.01 KiB) Viewed 297 times

I don't know if this is related to the problem or not, but a closer inspection of the devices shows that the hardware is not exactly the same between the newer and older units. You can see the difference on the backside of the device. The three-pin IC is rotated 90 degrees on the old vs new Doctors.

These "Charge Doctors" are very handy and I would like to get some more working units. Please advise if you see the same issue and what I can do about getting some more fully functional units.

[adafruit_support_mike]

The two boards are different hardware revisions.. there are also some differences in the silkscreen.

The fact that three devices from the same batch don't work is disturbing though.. I'll have someone pull a few units from inventory and check them.

[Nickel33]

What did the check of stock show? Did you find the same problem or am I just very unlucky?

[adafruit_support_mike]

Hi, we did find some other ones with the same error, and then checked everything we have in stock.

Send a note containing a link to this page and your order number to support@adafruit.com and the folks there will get you replacements for the two that don’t work.